I haven't come across any parasitic disease boards out there either (but then again, I'm not looking very hard). I've found the IBS peeps on HealingWell provide plenty of support and information, even if they're not infested
I am wary of other sites that claim everyone is infested with parasites and needs to be treated with this-or-that herbal cleanse or detox diet or de-gunker or something. I really don't think parasitic infections are entirely that common in the U.S. Outside of the U.S., definitely - I'd say most of the world's population does not have access to clean drinking water and the parasites run rampant in those situations. But even people who contract parasites abroad and come back to the U.S. normally heal without complications - even if they are not treated medically - because the body has many miraculous ways of healing itself.
At the time of my acute illness in Africa, I was having about 30 bouts of watery diarrhea per day; 10-20 episodes of vomiting per day; lost about 15 pounds; had fevers up to 104 degrees; stomach cramps, etc. Blech, indeed. I was treated with Flagyl and Cipro and recovered somewhat, but when I returned to the U.S. I was hospitalized for several days. The doctors at a major teaching hospital in Philadelphia could not locate the culprit. It was believed to be malaria at first because of the high fever, but my blood smear was negative. Colonoscopy and upper endoscopy, stool cultures, etc. were all negative. It was baffling. For the next several years I'd have episodes of illness that ranged (in my opinion) from "mild" (diarrhea less than 10 times a day) to "severe" (more than 30 times a day). Even the Mayo Clinic had no answers. I also tried sending my stuff to a lab in Arizona that specialized in parasite testing, but my results were negative.
I've taken Rifaximin, and didn't find that it helped, but evidently it is being used with success in the medical community for Small Intestinal Bacterial Overgrowth; research is being done on this condition but it might provide a clue for some of us weirdo mystery cases out there.
If you had a documented case of amoebiasis, it might be worth it to try a double whammy and ask your doctor about a Flagyl/Cipro combination for 10 days. I know it's not fun - I was nauseated as all get out and had bad headaches the whole time - but I did improve somewhat after those courses of antibiotics. C. diff is a problem with this for sure (never contracted it myself), so you have to weigh the pros/cons.
It's good you're seeing an infectious disease doctor. You should ask for copies of any blood work and other tests you've had. Often in the case of a parasitic infection there are some blood markers (elevated white cells, elevated eosinophils, some other stuff). Do you have copies of your labs?